This application is based on Japanese Patent Application No. 11-287935 filed Oct. 8, 1999, the contents of which are incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to a control apparatus for controlling an automotive vehicle having a plurality of vehicle drive units.
2. Discussion of Related Art
There is known a four-wheel-drive automotive vehicle of the type wherein front drive wheels are driven by an internal combustion engine, while rear drive wheels are driven by an electric motor. An example of this type of vehicle is disclosed in JP-A-10-67243. This type of four-wheel-drive vehicle has advantages of improved drivability owing to the provision of the four drive wheels, and a higher degree of fuel economy owing to normal vehicle running by the front wheels driven by the internal combustion engine, than a vehicle wherein the output of an internal combustion engine is mechanically transmitted to the front and rear drive wheels. Further, the vehicle can be run in an emergency mode by the rear wheels driven by the electric motor, even in the event of a failure of the internal combustion engine, until a battery for the electric motor is exhausted.
JP-A-10-67243 disclosing the four-wheel-drive vehicle does not address problems such as a defect taking place upon starting of an internal combustion engine, or a defect of a power transmitting mechanism disposed between the internal combustion engine and the front drive wheels. Nor does it disclose any solutions to such problems. Where a starter motor is provided for starting the internal combustion engine, there exist a problem that the starter motor is required to be comparatively large in size and weight, for the starter motor to have a normally required degree of durability, a problem that the internal to combustion engine cannot be suitably started in the event of a failure of the starter motor, and a problem that the vehicle cannot be run in an emergency mode in the event of a failure of the power transmitting mechanism disposed between the internal combustion engine and the drive wheels.
The prevent invention was made in view of the background prior art which has been discussed above. It is therefore a principal object of the present invention to provide a vehicle control apparatus which facilitates the starting of an internal combustion engine or permits the automotive vehicle to run even in the event of a failure of a power transmitting mechanism.
The above object may be achieved according to any one of the following modes of the present invention, each of which is numbered like the appended claims and depends from the other mode or modes, where appropriate, to indicate and clarify possible combinations of elements or technical features. It is to be understood that the present invention is not limited to the technical features or any combinations thereof which will be described for illustrative purpose only. It is to be further understood that a plurality of elements or features included in any one of the following modes of the invention are not necessarily provided all together, and that the invention may be embodied without some of the elements or features described with respect to the same mode.
(1) A control apparatus for controlling an automotive vehicle having drive wheels, an internal combustion engine provided as one drive unit for driving the vehicle, a starter motor for starting said internal combustion engine, a clutch device which is released to substantially disconnect a power transmitting path between the drive wheels and the internal combustion engine, and another drive unit operatively connected to drive wheels, the control apparatus comprising:
first engine-starting means for placing said clutch device a released state thereof and activating the starter motor to start the internal combustion engine, when the vehicle is running in a running condition in which the internal combustion engine cannot be started with a kinetic energy of the vehicle while the clutch device is placed in an engaged state thereof; and
second engine-starting means for placing the clutch device in the engaged state, to start the internal combustion engine with the kinetic energy of the vehicle, when the vehicle is running in a running condition in which the internal combustion engine can be started with the kinetic energy of the vehicle with the clutch device held in the engaged state.
In the vehicle control apparatus constructed according to the above mode (1) of this invention, the clutch device is released and the starter motor is activated by the first engine-starting means, to start the engine with the starter motor, when the running condition of the vehicle does not permit the internal combustion engine to be started with a kinetic energy of the vehicle with the clutch device in the engaged state. Further, when the vehicle running condition permits the internal combustion engine to be started with the kinetic energy, the clutch is engaged by the second engine-starting means, so that the internal combustion engine is started with the kinetic energy through the engaged clutch device. Thus, the provision of the first and second engine-starting means which are selectively operated facilitates the starting of the internal combustion engine. Further, the starting of the internal combustion engine with the kinetic energy of the vehicle reduces the required frequency of operation of the starter motor, making it possible to reduce the required capacity of the starter motor, resulting in reduced size and weight of the starter motor. The term xe2x80x9csubstantially disconnect a power transmitting pathxe2x80x9d does not necessarily mean that a plurality of clutches of the clutch device disposed between the drive wheels and the internal combustion engine are all placed in their released states for mechanically disconnecting the internal combustion engine and the drive wheels, but may mean a state of the power transmitting path in which a power of the internal combustion engine and a rotary motion of the drive wheels are not transmitted therebetween.
(2) A vehicle control apparatus according to the above mode (1), further comprising vehicle drive control means for placing the clutch device in the released state and operating the above-indicated another drive unit to drive the drive wheels for running the vehicle.
According to the above mode (2), the vehicle can be run with the above-indicated another drive unit, without an operation of the internal combustion engine.
(3) A vehicle control apparatus according to the above mode, wherein the first and second engine starting means are operable to start the internal combustion engine while the vehicle is running with the above-indicated another drive unit under the control of the vehicle drive means.
According to the above mode (3), the internal combustion engine can be started while the vehicle is running.
(4) A vehicle control apparatus according to the above mode (3), wherein the above-indicated another drive unit is an electric motor for driving the drive wheels, and the vehicle drive control means is motor drive control means for placing the clutch device in the released state and operating the electric motor for running the vehicle, the first and second engine-starting means being operable to start the internal combustion engine while the vehicle is running with the electric motor under the control of the motor drive control means.
(5) A vehicle control apparatus according to the above mode (4), wherein the internal combustion engine and the electric motor are provided to drive the same drive wheels.
(6) A vehicle control apparatus according to the above mode (1), wherein the internal combustion engine is provided to drive one of a pair of front drive wheels and a pair of rear drive wheels of the vehicle, and the above-indicated another drive unit is provided to drive the other of the pair of front drive wheels and the pair of rear drive wheels.
The vehicle control apparatus according to the above mode (6) of this invention is applicable to a 4-wheel-drive vehicle wherein one of the front and rear wheel pairs is driven by the internal combustion engine, and the other wheel pair is driven by another drive unit. In this arrangement, a mechanism connecting the internal combustion engine to the above-indicated one of the front and rear wheel pairs can be made simpler than in an arrangement in which the above-indicated another drive unit as well as the internal combustion engine is connected to the same wheel pair, for instance, to the pair of front drive wheels.
(7) A vehicle control apparatus for controlling an automotive vehicle having a pair of front drive wheels and a pair of rear drive wheels, and a plurality of drive units including an internal combustion engine for driving one of the pair of front drive wheels and the pair of rear drive wheels, and another drive unit for driving the other of the pair of front drive wheels and the pair of rear drive wheels, the vehicle control apparatus comprising an engine starting device operable to operate the above-indicated another drive unit for driving the above-indicated other of the pair of front drive wheels and the pair of rear drive wheels, to thereby start the internal combustion engine.
In the vehicle control apparatus according to the above mode (7) of the present invention, the above-indicated drive unit is operated by the engine starting device, to drive the above-indicated other pair of drive wheels which is not driven by the internal combustion engine, so that the internal combustion engine is started with a kinetic energy of the vehicle running with the above-indicated other pair of drive wheels rotated by the above-indicated another drive unit. This arrangement makes it possible to reduce the required size and weight of a starter motor if provided for starting the internal combustion engine as needed, or eliminates such an engine starter motor.
(8) A vehicle control apparatus according to the above mode (7), wherein the vehicle has a clutch device which is released to substantially disconnect a power transmitting path between the internal combustion engine and the above-indicated one of the pair of front drive wheels and the pair of rear drive wheels, and the engine starting device is operable after the vehicle has driven with an operation of the above-indicated another drive unit with the clutch device placed in a released state thereof, to place the clutch device in an engaged state thereof to thereby start the internal combustion engine with a kinetic energy of the vehicle.
In the vehicle control apparatus according to the above mode (8), the internal combustion engine is started after the vehicle speed has been considerably increased during running of the vehicle with the above-indicated another drive unit while the clutch device is in the released state. Accordingly, the load of the above-indicated another drive unit is reduced after the engine is started, and the load of a starter motor if provided for starting the internal combustion engine can be reduced, or the starter motor may be eliminated.
(9) A vehicle control apparatus for controlling an automotive vehicle having a pair of front drive wheels and a pair of rear drive wheels, a plurality of drive units including an internal combustion engine for driving one of the pair of front drive wheels and the pair of rear drive wheels and another drive unit for driving the other of the pair of front drive wheels and the pair of rear drive wheels, and a starter motor for starting the internal combustion engine, the vehicle control apparatus comprising:
starter-motor-defect determining means for determining whether the starter motor is defective; and
engine starting means operable when the starter-motor-defect determining means determines that the starter motor is defective, to operate the above-indicated another drive unit to drive the other of the pair of front drive wheels and the pair of rear drive wheels, for running the vehicle, to thereby start the internal combustion engine with a kinetic energy of the vehicle.
According to the vehicle control apparatus constructed according to the above mode (9) of this invention, the internal combustion engine is started with a kinetic energy of the vehicle running with the above-indicated other pair of drive wheels driven by the above-indicated another drive unit, when the starter-motor-defect determining means determines that the starter motor is defective. Thus, the internal combustion engine can be started even when the starter motor fails to normally function.
(10) A vehicle control apparatus for controlling an automotive vehicle having a plurality of drive units including a first drive unit for driving one of a pair of front drive wheel and a pair of rear drive wheels through a power transmitting mechanism, and a second drive unit for driving the other of the pair of front drive wheels and the pair of rear drive wheels, the vehicle control apparatus comprising:
transmitting-mechanism-defect determining means for determining whether the power transmitting mechanism is defective; and
provisional-vehicle-running control means operable when the transmitting-mechanism-defect determining means determines that the power transmitting mechanism is defective, to operate the second drive unit to drive the other of the pair of front drive wheels and the pair of rear drive wheels, for effecting provisional running of the vehicle.
According to the vehicle control apparatus constructed according to the above mode (10) of the present invention, the vehicle is provisionally run with the above-indicated other pair of drive wheels driven by the above-indicated second drive unit, when the transmitting-mechanism-defect determining means determines that the power transmitting mechanism through which the above-indicated one pair of drive wheels are driven by the first drive unit is defective. Thus, the vehicle can be run even when the power transmitting mechanism fails to normally function.
(11) A vehicle control apparatus according to the above mode (10), wherein the transmitting-mechanism-defect determining means determines whether the power transmitting mechanism fails to transmit a power of the first drive unit to the above-indicated one of the pair of front drive wheels and the pair of rear drive wheels.
According to the vehicle control apparatus according to the above mode (11), the vehicle can be run even when the power transmitting mechanism fails to normally operate to transmit power from the first drive unit to the above-indicated one pair of drive wheels.
(12) A vehicle control apparatus according to the above mode (10), wherein the provisional-vehicle-running control means operates the second drive unit with an energy generated by the first drive unit while the power transmitting mechanism is defective.
According to the above mode (12), the second drive unit is operated with an energy generated by the first drive unit when the power transmitting mechanism is defective. For instance, a rotary energy generated by an internal combustion engine provided as the first drive unit for driving a pair of front drive wheels is used to operate an electric generator to generate an electric energy, which in turn is used to operate an electric motor provided as the second drive unit for driving a pair of rear wheels. In this case, the vehicle is provisionally run with the rear drive wheels rotated by the electric motor in the event of a failure of the power transmitting mechanism. Since the electric motor is operated with the electric energy generated by the electric generator operated by the internal combustion engine, the vehicle can be run a relatively long distance, irrespective of the electric energy amount stored in a battery connected to the electric motor.